1. Field of the Invention
The invention relates to a fuel injection device for an internal combustion engine.
2. Description of the Prior Art
A fuel injection device is known from the market, which can be used to inject fuel directly into a combustion chamber of an internal combustion engine with which it is associated. To this end, a valve element is situated in a housing, which in the region of a fuel outlet opening, has a pressure surface that on the whole, acts in the opening direction of the valve element. At the opposite end of the valve element, there is a control surface that acts in the closing direction and delimits a control chamber. The control surface acting in the closing direction is on the whole larger than the pressure surface acting in the opening direction when the valve element is open.
When the fuel injection device is closed, a higher fuel pressure such as the pressure supplied by a fuel accumulator line (rail) acts on a region of the pressure surface acting in the opening direction and on the control surface acting in the closing direction. To open the valve element, the pressure acting on the control surface is reduced until the hydraulic force resultant acting on the pressure surface in the opening direction exceeds the force acting in the closing direction. This achieves an opening of the valve element.
A requirement for the function of this fuel injection device is a seal between the region in which the comparatively small pressure surface acting in the opening direction is situated and the region of the valve element in which the comparatively large control surface acting in the closing direction is situated. In the known fuel injection device, leakage fluid is conveyed out of the region of the seal via a leakage line.
The object of the present invention is to modify a fuel injection device of the type mentioned at the beginning so that it is as simple and inexpensive as possible and can be used at a very high operating pressure. In addition, the fuel injection device should function reliably, even when there are production tolerances.